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Category: Diseases

Hot and sticky summer weather = brown patch and Pythium

(Megan Kennelly, KSU Plant Pathology)

 

Is this brown patch in a tall fescue home lawn? Look for lesions to be sure! See below!

It’s that time of year when you go outside in the morning and immediately start to sweat. Ugh.

High humidity means that the temperatures stays high even overnight. Sticky, humid nights = conditions ripe for brown patch and foliar Pythium.

Brown patch is common in tall fescue lawns, perennial ryegrass athletic fields and fairways, and bentgrass putting greens. I’ve been hearing reports of brown patch popping up in the past few days.

Foliar Pythium is common in bentgrass and rye fairways, and we occasionally see it in lawns that are very lush and wet. Foliar Pythium is very rare on greens. I haven’t seen any yet, but with humidity and nighttime lows in the 70s it’s a possibility.

Fungicides and cultural practices for both diseases are spelled out in detail in the publication Chemical Control of Turfgrass Diseases.

 

In tall fescue, brown patch symptoms can resemble drought or other injury. If in doubt, check around for the characteristic lesions:

Both diseases can produce mycelium in the turf during wet, humid, dewy mornings. With Pythium, usually the turf looks matted down and greasy.

Brown patch:

Pythium – grass is matted down and greasy/mushy:

Not sure? You can always send a sample to the KSU Plant Diagnostic Lab.

A Homeowner Step-By-Step Buffalograss Lawn Guide

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Buffalograss Lawn Calendar

For more information check out the Buffalograss Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1447

Buffalograss has become more popular in recent years due to its reputation as a low-maintenance grass. Buffalograss does require less water and fertilizer than our other turfgrasses but often has problems competing with weeds in eastern Kansas. Remember, buffalograss is a low-maintenance lawn and not a “No”-maintenance lawn.

Buffalograss is an open growing grass that will not shade the soil as well as most of our other turfgrasses. Weeds are often the result. A regular mowing schedule can reduce broadleaf weed problems as most broadleaves cannot survive consistent mowing. Those that do either have a rosette growing pattern (dandelions, shepherds purse) or are “creepers” (henbit, chickweed, spurge). Annual grasses such as crabgrass or foxtail can also be a problem. A good weed preventer (prodiamine, pendimethalin or dithiopyr) may be needed prevent problems.

March

Spot treat broadleaf weeds if necessary. The most important treatment for broadleaf weeds should be in late October to early November well after the buffalograss is dormant. Treatments are much more effective then than in the spring as the weeds are smaller and the weeds are sending energy, as well as the herbicide, to the roots. Treatments in March are to take care of any “escapes” missed in the fall spraying. Spray early enough in March that the buffalograss is still dormant. Look at the base of the plants to make sure there is no green. Treat on a day that is 50 degrees F or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.  Use a combination product such as Trimec, Weed-B-Gon or Weed-Out. Weed Free Zone is also good and will give quicker results under cool conditions.

April

Apply crabgrass preventer between April 1 and April 15, or apply preventer when the eastern redbud is in full bloom. If using a product with prodiamine (Barricade), apply two weeks earlier.  Crabgrass preventers must be watered in before they will work. Avoid using broadleaf herbicides as the buffalograss is greening up as injury can result. The buffalograss will not be killed but growth will slow making the buffalograss less competitive with weeds.

June

Fertilize with 1 lb. of nitrogen per 1,000 square feet during June. More applications will give a deeper green color, but can encourage weeds. If it is felt that a second application is needed, apply in July.

If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. Again, I would only treat if grubs have been a problem in the past. Note that the whole area may not need to be treated. The beetles that lay the eggs for the grubs are attracted to lights and moist soil and those areas are most likely to be infested.

Late-July through August

If you see grub damage, apply a grub killer. If imidacloprid has been applied or if grubs have not been a problem in the past, this should not be necessary. Grub killers must be watered in immediately.

Late October to Early November

Spray for broadleaf weeds if they are a problem. Look carefully as our winter annuals such as chickweed and henbit are small and easily overlooked. Use a product that contains 2,4-D as it increases effectiveness on dandelions. Treat on a day that is at least 50 degrees F. Rain or irrigation within 24 hours reduces effectiveness. Use the rates listed on the label for all products mentioned.

For more information check out the Buffalograss Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1447

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

A Homeowner Step-by-Step Guide to Bermudagrass and Zoysiagrass Lawns

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Earlier I posted the Homeowner Step-By-Step Guide to Cool-Season Lawns in Kansas so I decided that it would be good to go ahead and get the warm-season lawn calendar out there for everyone that is manageing zoysiagrass, bermudagrass.

The following is a lawn calendar for zoysiagrass and bermudagrass. Buffalograss, also a warm-season grass, but we will cover that separate because the management of buffalograss is a little different then zoysiagrass and bermudagrass.

For more information check out the Zoyisagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1451

For more information check out the Bermudagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=586

 

Zoysiagrass and Bermduagrass Lawn Calendar

March
Spot treat broadleaf weeds if necessary. Treat on a day that is 50 degrees F or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.

April
Apply crabgrass preventer between April 1 and April 15, or apply preventer when the eastern redbud is in full bloom. This year we are getting a little warmer sooner but remember this cold snap that we just had would have killed any crabgrass if it had germinated. If using a product with prodiamine (Barricade), apply two weeks earlier. Crabgrass preventers must be watered in before they will start to work.

May – August 15
Fertilize with 1 lb. of nitrogen per 1,000 square feet per application. Follow the recommendations on the bag. More applications will give a deeper green color, but will increase mowing and may lead to thatch buildup with zoysiagrass. Bermudagrass can also have problems with thatch buildup but thatch is less likely with Bermuda than zoysia. Bermudagrass – Use two to four applications. Zoysiagrass – Use one to two applications. Too much nitrogen leads to thatch buildup.

One Application: Apply in June.
Two Applications: Apply May and July.
Three Applications: Apply May, June, and early August.
Four Applications: Apply May, June, July, and early August.

Remember to look and see if you are using a quick release nitrogen source or a slow release nitrogen source.  If you use a quick release source then it is immediately available but only lasts a couple weeks.  Thats why you would have to make a couple of applications like it is listed above.  If you are going to use a slow release source it will tell you on the bag how long the product will last.  Therefore, you might not have to make as many applications.

So generally you want to use a total of 2 to 4lb. of nitrogen per 1,000 square feet per year for bermudagrass and 1 to 2 lb. of nitrogen per 1,000 square feet per year for zoysiagrass.

June
If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. June is a good time to core aerate a warm-season lawn. Core aeration will help alleviate compaction, increase the rate of water infiltration, improve soil air exchange and help control thatch.


Late-July through August
If you see grub damage, apply a grub killer. If Imidacloprid has been applied, this should not be necessary. Grub killers must be watered in immediately.

Late October
Spray for broadleaf weeds if they are a problem. Treat on a day that is at least 50 degrees F. Rain or irrigation within 24 hours reduces effectiveness. Use the rates listed on the label for all products mentioned.

For more information check out the Zoyisagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1451

For more information check out the Bermudagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=586

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

Guess what KS city is listed as #7 in the Top 10 Worst Cities for Weeds and Disease for 2018?

(By Jared Hoyle, KSU Turfgrass Research and Extension)

As I was looking through some news articles I came across this one that caught my eye.

 “Top 10 Worst Cities for Weeds and Disease in 2018”

I couldn’t wait to click the article and see what the National Association of Landscape Professionals listed as the top 10 worst cities for weeds and disease.  It was also pretty interesting how they came up with these cities.  Check it out!

Guess what KS city is listed as #7?

http://www.kltv.com/story/37912381/weed-watch-the-top-10-worst-cities-for-weeds-and-lawn-disease-in-2018

 

A Homeowner Step-By-Step Tall Fescue and Kentucky Bluegrass Lawn Guide

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Homeowner Do-It-Yourself Lawn Calendar for Cool-Season Grasses

The following suggestions are for cool-season grasses such as Kentucky bluegrass or tall fescue. Zoysiagrass, bermudagrass, and buffalograss are warm-season grasses and require a different maintenance regime.

March
Spot treat broadleaf weeds if necessary. Treat on a day that is 50 degrees or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.

DSCN0010April
Apply crabgrass preventer (Or maybe even a little bit sooner this year) when redbud trees are in full bloom, usually in April. The preventer needs to be watered in before it will start to work. One-quarter inch of water will be enough to water in any of the products mentioned in this calendar.  Remember that a good, thick lawn is the best weed prevention and may be all that is needed.

May
Fertilize with a slow-release fertilizer if you water your lawn or if you receive enough rainfall that your turf normally doesn’t go drought-dormant during the summer. If there are broadleaf weeds, spot treat with a spray or use a fertilizer that includes a weed killer. Rain or irrigation within 24 hours of application will reduce effectiveness of the weed killer, but the fertilizer needs to be watered in. If you are using a product that has both fertilizer and weed killer, wait 24 hours after application before watering in.

June through Mid-July
Apply second round of crabgrass preventer by June 15 – unless you have used Dimension (dithiopyr) or Barricade (prodiamine) for the April application. These two products normally provide season-long control with a single application. Remember to water it in. If grubs have been a problem in the past, apply a product containing imidacloprid during the first half of July. This works to prevent grub damage. It must be watered in before it becomes active.

IMG_0563Late-July through August
If you see grub damage, apply a grub killer that contains Dylox. Imidacloprid is effective against young grubs and may not be effective on late instar grubs. The grub killer containing Dylox must be watered in within 24 hours or effectiveness drops.

September
Fertilize around Labor Day. This is the most important fertilization of the year. Water in the fertilizer.

November
Fertilize. This fertilizer is taken up by the roots but is not used until the following spring. Water in fertilizer. Spray for broadleaf weeds even if they are small. Broadleaf weeds are much easier to control in the fall than in the spring. Spray on a day that is at least 50 degrees. Rain or irrigate within 24 hours reduces effectiveness. Use label rates for all products!

For more information on Tall Fescue Lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1460 

For more information on Kentucky Bluegrass Lawns- https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=816

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

Cut down and destroy dead pines to help prevent spread of pine wilt

Now you see it:

call-hall-2012-10-09_17-20-05_109

Now you don’t:

Call-Hall-now-gone-2012-10-25_17-20-32_596

This tree had pine wilt disease, and it was cut down and chipped or burned to reduce the risk of spread to other trees.

Pines have several disease and insect problems. One of them is pine wilt disease. It kills the entire tree quickly.

Pine wilt is caused by the pinewood nematode, a microscopic worm. The nematode is spread by the pine sawyer beetle. The nematode feeds and multiplies in the tree’s resin canals, causing wilting and death in several weeks to several months. The nematode and beetles spend the winter in the infected tree. In spring, the beetles emerge starting around May 1, carrying nematodes to new trees and continuing the cycle of infection.

The disease is common in the eastern half of the state and has gradually spread west. There have been pockets of infection in the western part of the state, but we’d like to keep it out. Also, sanitation efforts will help reduce spread even in the east where the disease is common. Here is a map of pine wilt from our Kansas Department of Agriculture colleagues based on recent survey data:

 

 In Kansas, new pine wilt infections are most visible from August to December. Trees wilt and die in a short period of time, from several weeks to a few months. In the first stages, the needles turn grey or green, then yellow and brown. The discoloration sometimes occurs branch by branch, sometimes all at once. With pine wilt, eventually the whole tree dies, within a few months. The brown needles stay on the tree for up to a year after the tree has died. Another key symptom is reduced resin. On a healthy tree, sticky resin bleeds from the site of a wound. In contrast, if a tree has pine wilt the resin is often reduced or absent, and branches become dry or brittle.

There is a website with color photos and descriptions at the following link:

http://muextension.missouri.edu/explorepdf/miscpubs/mx0858.pdf

There are images to compare and contrast pine wilt with other pine diseases here:

http://www.ksre.ksu.edu/bookstore/pubs/l722.pdf

With the other diseases (tip blight, needle blight) only parts of the tree turn brown. With pine wilt, the whole tree is brown and dead.

If you aren’t sure if your tree has pine wilt or something else, contact your local K-State Research and Extension Office or the K-State Diagnostic Lab (clinic@ksu.edu).

If a tree has pine wilt,  the tree should be cut down by  April 1  to make sure there is time to destroy the wood by May 1, when the beetles start to some out. Cut the tree to the ground—don’t leave a stump. Chip or burn the wood immediately to destroy the beetles and nematodes. Don’t keep pine wood around for firewood.

Large patch activity in research plots

Cool, wet weather has triggered large patch activity in golf courses – and in our research plots.

The photos below are from an ongoing research trial. You can read some details about the study in our online research update from spring. PhD student Mingying Xiang is the lead researcher on this study, under the mentorship of Megan Kennelly and Jack Fry.

The photos below show different zoysiagrass breeding lines. For each plot, one side was inoculated in Sept 2016, and the other side is protected with fungicides to allow ongoing rating of quality and agronomic traits in the absence of disease AND to serve as a “healthy check.”

As you glance through the photos, you can clearly see the large patch on the inoculated sides of many of the plots, while the fungicide-treated side is clean. However, you will also see plots where you can’t even tell which side is which. That is, even the inoculated, non-fungicide-treated side is looking clean. We are hoping those  may be resistant lines to examine in further testing. Stay tuned! Turfgrass breeding takes a long time!

Last hiccups of summer diseases

Early last week we saw a couple last gasps of the summer diseases, with some Pythium on a tall fescue lawn:

It was greasy, it was mushy, and after “a night in the box” there was classic Pythium mycelium. Foliar Pythium is rare on tall fescue lawns, usually coming in during very wet weather on sites that have received a little too much water and perhaps a little too much N. When this one came in, it was after one last blast of some heat, but with cool, cool temps on the horizon. Now that we are coming into this nice, consistent cool weather it’s really too late to consider fungicides, and instead we can concentrate on fall renovations AND tweaking cultural practices to help reduce disease risk next year. There was also a last hiccup of brown patch from a golf course fairway. Same story – with lows in the low 60s and even 50s, those diseases should stay quiet and hopefully we won’t see them until 2018.

Next door in Missouri, Dr. Miller is reporting some continued sightings of Pythium root rot (which is different from foliar Pythium) and basal anthracnose. I would agree we are not out of the woods yet. You can see his photos HERE.

Start thinking about large patch applications now if you aren’t already

Photo – large patch symptoms in spring

We humans are enjoying the cool weather, and our cool-season grasses are too. However we are coming up on the time when our warm-season grasses start to shut down, and the season when the large patch pathogen likes to infect our zoysia. Sometimes we see symptoms in fall if conditions are very cool and wet. I have not seen any around here yet, but in Missouri some is firing. Our main time of seeing the symptoms is spring.

In Kansas, applications in September have been quite effective in reducing symptoms through most or all of the following spring. With this early cool weather, leaning towards earlier rather than later in the month may be wise. Next door in Missouri they’ve seen good results with EARLY spring applications as well – read about it HERE in Dr. Miller’s excellent post about application timing.  In Kansas, when we’ve tried mid/late spring applications when symptoms are already pretty apparent, they don’t work well, if at all. For details on the newest products you can check the large patch section here (click to page 18)

http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf

 

Here is a video with some descriptions of the biology and symptoms:

 

Grey Leaf Spot – All the way from 2015.

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Someone told me and I am not sure if it is correct or not, “that grey leaf spot will infect crabgrass before it hits our desirable turfgrass species”.  The other day I saw some grey leaf spot crabgrass in a ryegrass lawn and got me thinking that this is about the time grey leaf spot starts to kick in around here.  I went back through the blogs and back in 2015 (Actually August 25, 2015) I posted about grey leaf spot.

I wanted to pass along the blog again for everyone that may have had grey leaf spot in the past.

http://blogs.k-state.edu/turf/grey-leaf-spot/

Also check on  more control options for grey leaf spot in this publication – http://www2.ca.uky.edu/agc/pubs/ppa/ppa1/ppa1.pdf

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf